<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        .box1 {
            width: 200px;
            height: 200px;
            background-color: gold;
            margin-bottom: 200px;
        }
        /* 
            margin重叠后，margin最终的值是取大优先
        */
        .box2 {
            width: 200px;
            height: 200px;
            background-color: skyblue;
            margin-top: 201px;
        }
    </style>
</head>

<body>
    <div class="box1"></div>
    <div class="box2"></div>
</body>

</html>